{
  "abstract": "We present a field-level inference framework for testing gravity with large-scale structure, exploiting the full information of the galaxy distribution. Traditional analyses based on the power spectrum discard non-Gaussian and Fourier phase information, resulting in strong degeneracies between modified gravity (MG) and galaxy bias. Our approach overcomes this limitation by performing a Bayesian analysis directly on the three-dimensional galaxy number counts, jointly constraining MG and bias parameters using both amplitudes and phases. As an illustrative application, we analyse mock data in real space in the context of f(R) gravity and a non-linear galaxy bias model designed to mimic the real-data 2M++ BORG analysis. Non-linear structure formation is modelled using COmoving Lagrangian Acceleration (COLA) under different gravity strengths, parameterised by fR0. The resulting dark-matter fields are then mapped to mock galaxy catalogues via a non-linear bias prescription. We demonstrate that, with the initial phases assumed known, including non-Gaussian and phase information yields tighter constraints on both fR0 and the primary bias parameter β (corresponding to the linear galaxy bias on large scales), relative to power-spectrum-only analyses. Notably, the field-level approach breaks the degeneracies between MG and galaxy bias inherent to two-point statistics. Through a cosmic-web classification into voids, walls, filaments and clusters, we find that under-dense regions are the primary drivers in distinguishing gravity at the field level. Finally, we establish the robustness of our pipeline against variations in initial conditions, Poisson noise, and galaxy-field thresholding, providing a powerful path forward for field-level tests of gravity.",
  "abstract_shown": true,
  "affiliations": [
    "Institute of Cosmology and Gravitation, University of Portsmouth, Dennis Sciama Building , Burnaby Road, Portsmouth, PO1 3FX ,",
    "Durham University Institute for Computational Cosmology, Department of Physics, , South Road, Durham DH1 3LE ,",
    "Kavli IPMU (WPI), UTIAS, The University of Tokyo , Kashiwa, Chiba 277-8583 ,",
    "Yukawa Institute for Theoretical Physics , Kyoto University, Kyoto 606-8502 ,"
  ],
  "article_type": null,
  "arxiv": null,
  "author_total": 4,
  "authors": [
    {
      "affs": [
        0
      ],
      "name": "Sophie Hoyland",
      "orcid": "0009-0008-8335-5785"
    },
    {
      "affs": [
        0,
        1
      ],
      "name": "Daniela Saadeh"
    },
    {
      "affs": [
        0,
        2,
        3
      ],
      "name": "Kazuya Koyama"
    },
    {
      "affs": [
        0
      ],
      "name": "Harry Desmond"
    }
  ],
  "bibtex": "https://research.draconitic.com/paper/82yz7jeabygv3.bib",
  "cited_by": 0,
  "doi": "10.1093/mnras/stag1888",
  "fulltext_url": null,
  "id": "82yz7jeabygv3",
  "issns": [
    "0035-8711",
    "1365-2966"
  ],
  "landing_url": "https://academic.oup.com/mnras/advance-article/doi/10.1093/mnras/stag1888/8869232",
  "language": null,
  "licence": "CC-BY-4.0",
  "licence_label": "CC BY 4.0",
  "licence_source": "article",
  "licence_url": "https://creativecommons.org/licenses/by/4.0/",
  "metadata_licence": null,
  "native_subjects": [
    [
      "openalex",
      "3103|Cosmology and Gravitation Theories"
    ]
  ],
  "openalex": "W7167574861",
  "pdf_url": "https://academic.oup.com/mnras/advance-article-pdf/doi/10.1093/mnras/stag1888/71629205/stag1888.pdf",
  "pmcid": null,
  "pmid": null,
  "published": "2026-10-06",
  "publisher": "Oxford University Press (OUP)",
  "ris": "https://research.draconitic.com/paper/82yz7jeabygv3.ris",
  "sources": [
    {
      "first_seen": "2026-10-30T12:18:17Z",
      "native_id": "10.1093/mnras/stag1888",
      "source": "crossref",
      "url": "https://academic.oup.com/mnras/advance-article/doi/10.1093/mnras/stag1888/8869232"
    }
  ],
  "subjects": [
    {
      "field": "astronomy",
      "origin": "openalex:3103|Cosmology and Gravitation Theories",
      "subfield": "cosmology"
    }
  ],
  "title": "Disentangling modified gravity and galaxy bias with field-level inference",
  "title_text": "Disentangling modified gravity and galaxy bias with field-level inference",
  "type": "peer-reviewed",
  "updated_at": "2026-10-30T12:18:17Z",
  "url": "https://research.draconitic.com/paper/82yz7jeabygv3",
  "venue": "Monthly Notices of the Royal Astronomical Society",
  "versions": []
}